Stewart p



UNITED? STATES PATENT men,

THE WINDSOR COMPANY, OF SAME PLACE.

PROCESS OF PRODUCI'NG WHITE EFFECTS ON FABRICS;

SPEQIFIOA'IIONfOiming part of Letters Patent No. 606,776, dated July 5, 1898. Application filed October 28, 1897. Serial No. 656,722. (No specimens.)

T0 (0Z6 whom it may concern.-

Be it known that I, STEWART F. CARTER, a subject of the Queen of GreatBritain, residing at North Adams, in' the county of Berkshire and State of Massachusetts, have invented a certain new and useful Improvement in Processes of Producing White Effects 011' Cotton and other Fabrics, of which the following is a specification.

The object of .my invention is to produce white effects upon fabrics which will be more durable than is possible with prior processes.

In calico-printing and in the printing of other fabrics prior to my invention with white effects it has been the custom to imprint upon the fabric a suitable white pigment, such as oxid of zinc or sulfate of barium, to which albumen. is added, and to subject the fabric to the effect of steam, by which the albumen is coagulated. This coagulation of the albumen has resulted in the mechanical fixing of the color, .but only to an imperfect extent, since the color can be and frequently is removed and disfigured by the friction occasioned by ordinary use. It has also been suggested, and it has been practiced to a limited extent, to imprint upon. the fabric tungstate of soda to which gum or starch has been added, the fabric being subsequently passed through a solution of barium chlorid, the chemical reaction resulting in the formation of tungstate of barium, which is an insoluble white pigment and which produces the color effect desired, and also in the formation of sodium chlorid, which of course dissolves out. It has also been proposed that the process last referred to be reversed and to imprint upon the fabric with barium chlorid, the fabric being subsequently passed through a bath of tungstate of soda. With either of the processes just referred to the color is still too fugitive to meet all the requirements of use.

I have discovered that a sulfocarbonate of cellulose when applied to afabric and subjected to heat, so as to be decomposed, possesses the property of adhering with such tenacity to the fabric as to be practically incapable of removal, and, basing my invention upon this discovery, I add to such a sulfocarbonate of cellulose a suitable white pigment,

the tungstate of soda.

preferably tungstate of barium, which when the former is subjected to heat will be fixed with almost absolute permanence upon the fabric. a The sulfocarbonate of cellulose to which I have referred and which I use in carrying out my improved process is known on the market as viscose, and it is prepared in accordance with the terms of Letters Patent of the United States No. 520,770, dated June 5, 1894, granted to Henry G. Nichols, trustee, and to which reference is made for the method of production and the chemical properties of such substance.

In carrying out my invention I prefer to proceed as follows: A suitable aqueous solution of viscose is obtained, such as is referred to in said patent, and to such solution is added, by preference, tungstate of soda. The relative proportions of these substances depend upon the intensity of the pattern desired; but for ordinary work such proportions may be five pounds of tungstate of soda to one gallon of the viscose solution. with this mixture in any suitable way and with any suitable patterns. After the printing has been effected the fabric is subjected to a sufficient heat to decompose the viscose, causing the same to unite tenaciously with the fabric and forming a bond for the pigment, which is to be subsequently produced from The temperature to which the fabric should be subjected may vary between 160 and 200 Fahrenheit, and preferably should be produced by the action of free steam, as is common in the art of calico-printing. After the removal of the fabric from the heating-room in which the decomposition of the viscose has been effected the fabric is passed through a suitable bath of barium chlorid, resulting, as before stated, in the formation of tungstate of barium in the form of a white precipitate, which will be bonded tenaciously to the fabric by reason of the peculiar property of viscose which I have discovered and to which I have referred. After being passed through the barium-bath the fabric may be washed and bleached, if required, although I find that by the use of tungstate of barium little or no after bleaching is necessary, owing to its intense whiteness.

The fabric is printed I have found in practice that white colors, and particularly those produced by tungstate of barium when applied as I have explained, are so tenaciously aflixed to the fabric that the latter can be washed, bleached, and even passed through acids without destroying or even affecting the colors in any way.

It will be obvious that instead of adding to the viscose tungstate of soda and passing the fabric through a bath of barium chlorid it will be possible to imprint upon the fabric with the barium chlorid and to pass the fabric through a bath of tungstate of soda, the identical chemical reaction taking place in the latter case as in the former. It is also to be understood that instead of producing tungstate of barium upon the fabric, as I have explained, by first imprinting thereon with tungstate of soda or barium ehlorid and subsequently subjecting the fabric to a bath of one or the other, as the case may require, precisely the same effect will be obtained if the tungstate of barium is first produced by add ing to the tungstate of soda the desired quantity of barium chlorid. I11 the latter case the tungstate of barium, which will form as a heavy white precipitate, will be mixed with the viscose imprinted upon the fabric and simply subjected to heat, so to decompose the viscose and intimately aftix the pigment, as explained. The principal advantage of first producing the tungstate of barium as just explained is that it does away with the necessity of passing the fabric through the bath of barium chlorid or tungstate of soda, as the case may be, and also enables the tungstate of barium to be maintained at hand in bulk for use as exigencies may require. Another advantage of using the tungstate of barium in the first instance and without the bath, as first explained, is that by so doing other colors may be applied to the fabric at the same operation and some of which, if a bath were used, might be affected.

Although I preferto employ a pigment comprising tungstate of barium, as I find in practice that such apigment appears to possess the greatest practical advantages, still it will be understood that other pigments may be used and be bonded or affixed permanently to the fabric by the employment of viscose or a sulfocarbonate of cellulose, as I have explained. Among theseother pigments which may be used may be mentioned barium sulfate, with which I have experimented and which may be produced by passing the fabric through a bath of sodium sulfate after the printing has been effected with the barium chlorid. I find, however, that barium sulfate does not possess the covering qualities of barium tungstate, and I therefore do not consider the same so desirable.

The essence of my invention residing in the discovery which I have made that a sulfocarbonate of cellulose, such as viscose, when applied to a fabric and subjected to heat possesses the property of adhering to the fabric with such tenacity as to be practically incapable of removal I wish to have my invention understood as covering that discovery without being limited to the particular pigment or pigments which may be bonded or affixed to the fabric by such a bonding agent.

Having now described my invention, what I claim as new therein, and desire to secure by Letters Patent, is as follows:

1. The improved process for producing white effects on cotton an d other fab rics,which consists in first subjecting the fabric to the action of a sulfocarbonate of cellulose, such. as viscose, in imprinting designs upon the fabric with a suitable pigment, and in subjecting the fabric to heat so as to decompose the viscose, substantially as set forth.

2. The improved process for producing white effects on cotton and other fabrics,which consists in subjecting the fabric to the action of a sulfocarbonate of cellulose, such as viscose, in imprinting designs upon the fabric with tungstate of barium, and in subjecting the fabric to heat so as to decompose the viscose, substantially as set forth.

3. The improved process for producing white effects 011 cotton and 0therfabricsuvhich consists in imprinting designs upon the fabric with a mixture of viscose and tungstate of soda; then in subjecting the fabric to heat so as to decompose the viscose; and finally, in passing the fabric through a bath of barium chlorid, so as to form upon the fabric tungstate of barium in the form of the designs, substantially as set forth.

This specification signedaud witnessed this 19th day of October, 18517.

Witnesses:

FRANK L. Dvnn, Jam. 11.. T. vnon. 

